Medical snare

Abstract

Snares for retrieval of medical devices from the body of an animal, medical assemblies, kits, and methods of retrieving a medical device from the body of an animal are described. An example snare comprises an outer sheath defining an outer sheath lumen; an elongate member disposed in the outer sheath lumen and having a longitudinal axis and at least one elongate member lumen; a capture member disposed and axially movable within the at least one elongate member lumen, the capture member defining a capture loop having a throat region and a portion extending along a plane that is perpendicular to the longitudinal axis of the elongate member; and a threader member disposed and axially movable within the at least one elongate member lumen, the threader member defining a threader loop. A handle includes a rotatable control member for deflecting a distal end of the outer sheath.

We claim: 
     
         1 . A snare, comprising:
 an outer sheath defining an outer sheath lumen;   an elongate member disposed in the outer sheath lumen and having a longitudinal axis and at least one elongate member lumen;   a capture member disposed and axially movable within the at least one elongate member lumen, the capture member defining a capture loop having a throat region and a portion extending along a plane that is perpendicular to the longitudinal axis of the elongate member; and   a threader member disposed and axially movable within the at least one elongate member lumen, the threader member defining a threader loop.   
     
     
         2 . The snare of  claim 1 , wherein the at least one elongate member lumen comprises first, second, third, and fourth elongate member lumens. 
     
     
         3 . The snare of  claim 2 , wherein the capture member is disposed within one of the first, second, third, and fourth elongate member lumens; and
 wherein the threader member is disposed within another of the first, second, third, and fourth elongate member lumens.   
     
     
         4 . The snare of  claim 2 , wherein the capture member defines first and second capture member legs; and
 wherein the first capture member leg is disposed in the first elongate member lumen and the second capture member leg is disposed in the second elongate member lumen.   
     
     
         5 . The snare of  claim 4 , wherein the capture loop defines a second portion extending from the first portion and along a plane disposed at a non-parallel and non-orthogonal angle to the longitudinal axis of the elongate member. 
     
     
         6 . The snare of  claim 4 , wherein the threader member defines first and second threader member legs; and
 wherein the first threader member leg is disposed in the third elongate member lumen and the second threader member leg is disposed in the fourth elongate member lumen.   
     
     
         7 . The snare of  claim 6 , further comprising a handle attached to the elongate member, the handle including a plunger attached to the first and second threader member legs. 
     
     
         8 . The snare of  claim 7 , further comprising at least one pull wire having a first end attached to a movable component of the handle and a second end attached to a distal end of the outer sheath;
 wherein movement of the movable component of the handle results in deflection of the distal end of the outer sheath.   
     
     
         9 . The snare of  claim 8 , wherein the handle further comprises a second movable component that controls movement of the first movable component. 
     
     
         10 . The snare of  claim 9 , wherein the second movable component comprises a control member rotatable along an axis of the handle. 
     
     
         11 . The snare of  claim 10 , wherein the control member defines a frustoconical portion. 
     
     
         12 . The snare of  claim 1 , wherein the capture member and the threader member comprise nitinol. 
     
     
         13 . The snare of  claim 1 , wherein the capture member and the threader member comprise stainless steel. 
     
     
         14 . The snare of  claim 1 , wherein the capture member and the threader member comprise stainless steel coated with polytetrafluoroethylene. 
     
     
         15 . The snare of  claim 1 , wherein the outer sheath comprises a reinforced sheath. 
     
     
         16 . The snare of  claim 15 , wherein in the outer sheath comprises one of a braid and a coil. 
     
     
         17 . The snare of  claim 1 , wherein the outer sheath is adapted to be temporarily locked to the capture member to prevent relative axial movement between the outer sheath and the capture member. 
     
     
         18 . A snare, comprising:
 an outer sheath defining an outer sheath lumen;   an elongate member disposed in the outer sheath lumen and having a longitudinal axis and at least one elongate member lumen;   a capture member disposed and axially movable within the at least one elongate member lumen, the capture member defining a capture loop having a throat region, a first portion extending along a plane that is perpendicular to the longitudinal axis of the elongate member, and a second portion extending from the first portion and along a plane disposed at a non-parallel and non-orthogonal angle to the longitudinal axis of the elongate member; and   a threader member disposed and axially movable within the at least one elongate member lumen, the threader member defining a threader loop.   
     
     
         19 . A snare, comprising:
 an outer sheath defining an outer sheath lumen;   an elongate member having a longitudinal axis and disposed and axially movable within the outer sheath lumen, the elongate member having an elongate member proximal end, an elongate member distal end, and an elongate member main body extending between the elongate member proximal end and the elongate member distal end and having at least one elongate member lumen extending from the elongate member proximal end to the elongate member distal end;   a capture member disposed and axially movable within the at least one elongate member lumen, the capture member having a capture member proximal end and a capture member distal end, the capture member distal end defining a capture loop having a throat region, a first portion extending along a plane that is perpendicular to the longitudinal axis of the elongate member, and a second portion extending from the first portion, the second portion including the capture member distal end and extending along a plane disposed at a non-parallel and non-orthogonal angle to the longitudinal axis of the elongate member;   a threader member disposed and axially movable within the at least one elongate member lumen, the threader member having a threader member proximal end and a threader member distal end, the threader member distal end defining a threader loop; and   a handle attached to the elongate member, the handle including a plunger attached to the threader member.   
     
     
         20 . A method of retrieving a medical device from the body of an animal, comprising:
 navigating a distal end of the snare according to  claim 1  to a location within a vessel within the body of the animal at which the device to be retrieved is located;   distally advancing the capture member within the elongate member such that the capture loop exits the elongate member and the portion of the capture loop lies on a plane that is perpendicular to the lengthwise axis of the elongate member;   manipulating the capture loop such that a portion of the device to be retrieved is positioned within the throat region of the capture loop;   distally advancing the threader member within the elongate member such that the threader loop passes through the capture loop;   retracting the capture member within the elongate member such that the capture loop tightens around a portion of the device to be retrieved; retracting the elongate member such that the capture member, threader member, and the device to be retrieved move through the body vessel and exit the body of the animal.